Immunohistochemical study of 4-hydroxyaminoquinoline 1-oxide-induced rat malignant fibrous histiocytoma

The primary focus of this experiment was on the investigation of localizations of alpha 1-antitrypsin (alpha 1-AT), alpha 1-antichymotrypsin (alpha 1-ACT), fibronectin (FN) and lysozyme (LY) in tumor cells of experimental malignant fibrous histiocytoma (MFH). The induction of MFH was conducted by injecting Fischer 344 rats with 4-hydroxyaminoquinoline 1-oxide (4-HAQO). In 46 out of 50 rats, tumors were generated, all of which were diagnosed as MFH and classified into 5 subtypes, according to their histological properties. The presence of alpha 1-AT, alpha 1-ACT and FN in all MFH tumor cells was observed in the tumor cells of various types. Especially, fibroblast-like, histiocyte-like and Touton and/or Epulis type giant cells showed strong reactivity. However, positive reaction of LY in MHF tumor cells was very weak, or the reaction was negative. These findings are consistent with those of human MFH.